yeah the ending was pretty weak imo.
*spoiler alert*
it was so abrupt, it was like they ended it 80% through a mission or something. maybe i was expecting a boss battle or something (which i understand goes somewhat against the grain of the game), but it was like you kill a bunch of guys, re-program the missile real quick, kill 4 or 5 more guys, and then it just ended out of nowhere. it would have been cool to battle that chopper at the end or something, but then i guess that's been done to death in other games.